Liquid crystal polyesters are excellent, in flowability and resistance to burr formation, and also excellent in heat resistance, mechanical properties such as rigidity, chemical resistance, dimensional precision and the like. Therefore, the liquid crystal polyesters are increasingly used for electrical and electronic components having complex shapes. In particular, the liquid crystal polyesters are often used for connectors due to requirements for high performance electrical and electronic devices, such as requirements relating to mountability (reflow resistance, i.e. resistance to heat during reflow soldering), and high-density mounting and downsizing (flowability and resistance to burr formation).
Further height-reducing and downsizing in connectors are progressing in recent years, and thus higher performance is required for resin materials from which the connectors are made. This trend is notable for FPC or FFC connectors used for connecting a printed circuit board and a flexible printed circuit (FPC), or a flexible flat cable (FFC), for example.
The FPC or FFC connector is composed of a housing component (part) and an actuator component (part), both of which have a wide width. The housing supports the actuator component rotatably between a locked position and an unlocked position. The actuator component when fixed in the locked position applies contact pressure to the FPC or FFC inserted in an insertion opening.
In this fixation, the actuator component is desirably fixed by applying a pressure force to only one end of the actuator component. Thus, when the rigidity of the resin material is not sufficient, problems such as breakage of the actuator component and insufficient fixation of the FPC or FFC occur. Thus, there is a need for an actuator component composed of a highly rigid resin material.
There are some resin materials proposed as a highly rigid liquid crystal polyester resin composition, including a resin composition obtained by blending a liquid crystal polyester with silica fine particles (Patent Document 1) and a resin composition blended with mica and a specific carbon fiber (Patent Document 2).
However, improvement in rigidity provided by these resin compositions is not sufficient, and these resin compositions are inferior in followability and mechanical strength.
Generally, it was believed that rigidity conflicts to strength in liquid crystal polyester resin compositions, and thus providing the liquid crystal polyester resin composition excellent in both rigidity and strength in a balanced manner is difficult.    Patent Document 1: Japanese Patent Publication No. 2007-138143    Patent Document 2: Japanese Patent Publication No. 2011-094116